Free wheel clutch mechanism for bicycle drive train

Abstract

An exercise bicycle including a frame having a seat and handlebars, a high-inertia flywheel having a hub at a center of rotation, the flywheel being rotatably supported on the frame at the hub, and a drive train including a drive sprocket, a crank arm attached to and extending from the drive sprocket, and a pedal attached to the crank arm, the drive train being rotatably supported by the frame. The drive train also includes a slave sprocket fixed to the flywheel at the hub, with the drive and slave sprockets connected in a direct-drive relationship, the drive train driveable in a forward and rearward directions to cause the flywheel to rotate. A clutch mechanism is positioned in engagement with the slave sprocket and the hub to create a frictional engagement between the sprocket and the hub, and to establish a break-free force threshold. When the drive train is actuated in the forward direction, the slave sprocket and the hub move together, and when the drive train is actuated in the rearward direction under the influence of a force greater than the break-free force threshold, the clutch mechanism slips between the slave sprocket and the hub, allowing the slave sprocket and the flywheel to move independently of one another. The clutch mechanism including a spring tensioner whereby the break-free force may be adjusted.

We claim: 
     
       1. An exercise bicycle comprising:
 a frame including a seat and handlebars; 
 a flywheel including an axle housing, the flywheel being rotatably supported on the frame; 
 a drive train, including a drive train sprocket, a crank arm attached to and extending from the drive train sprocket, and a pedal attached to the crank arm, the drive train being rotatably supported by the frame, and a slave sprocket coupled to the flywheel, with the drive train and slave sprockets connected in a direct-drive relationship, the drive train drivable in a forward and rearward direction to cause the flywheel to rotate; 
 a one way bearing circumferentially mounted on the axle housing, the slave sprocket circumferentially mounted in engagement with the one way bearing; 
 a spring tensioner coupled to the axle housing; and 
 a clutch positioned to engage with the slave sprocket and the flywheel, the clutch including a biasing member positioned between the clutch and the spring tensioner, the clutch creating a break free force. 
 
     
     
       2. The exercise bicycle of  claim 1 , the biasing member being a Belleville washer. 
     
     
       3. The exercise bicycle of  claim 1 , the axle housing defining a cylinder wherein a outside circumference of the cylinder adjacent the clutch is threaded. 
     
     
       4. The exercise bicycle of  claim 3 , the spring tensioner defining a threaded aperture adapted to engage the threaded outside circumference of the axle housing. 
     
     
       5. The exercise bicycle of  claim 4 , wherein the spring tensioner is rotatable about the axle housing so as to increase or decrease the break free force. 
     
     
       6. The exercise bicycle of  claim 1 , the clutch including an inner clutch plate adjacent an inside edge of the slave sprocket, and an outer clutch plate adjacent an outer edge of the slave sprocket. 
     
     
       7. The exercise bicycle of  claim 6 , the clutch including an inner clutch washer positioned between the outer clutch plate and the slave sprocket, and an outer clutch washer positioned between the outer clutch plate and the slave sprocket. 
     
     
       8. The exercise bicycle of  claim 7  wherein the inner clutch washer and the outer clutch washer are polyethylene. 
     
     
       9. The exercise bicycle of  claim 2  wherein the spring tensioner defines an outwardly extending flange circumferential to the axle housing, the outwardly extending flange adapted to center the Belleville washer about the axle housing. 
     
     
       10. The exercise bicycle of  claim 1 , wherein the clutch comprises a clutch plate circumferentially disposed about the axle housing and operably connected with the slave sprocket. 
     
     
       11. The exercise bicycle of  claim 1 , wherein the clutch comprises a clutch plate circumferentially disposed about the axle housing and operably connected with the slave sprocket.